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Headphone CSD waterfall plots - Page 63

post #931 of 937

Maybe try to re-measure a few sets of data, each with some minor variations in the earcup placement on your measuring instrument? That could uncover what is causing this.

post #932 of 937
Quote:
Originally Posted by arnaud View Post

What is your measuring rig and procedure vid?

 

Artificial ear and ear canal leading to an electret capsule mic. An MLS signal.

 

Quote:
Originally Posted by jerg View Post

Maybe try to re-measure a few sets of data, each with some minor variations in the earcup placement on your measuring instrument? That could uncover what is causing this.

 

I'll see about doing it later today.

post #933 of 937

Using the programs from dsputils.zip (see description here), I have created a script for a fairly complete set of headphone measurements. I am not sure if anyone finds this useful, though, since the user friendliness and the documentation are lacking, but maybe someone will find it interesting:

  hptest.zip

 

It uses the following input files:

- the test signals recorded from the headphone (the test does take a few minutes, so the sample could be optimized for shorter length). resample.txt needs to be set up with the correct start time and gain parameters so that the 1 kHz tone at the beginning of the file starts at exactly 1 second, and has an amplitude of 0 dBFS

- the impedance test file (a loopback recording using a device with a known resistive output impedance; the test signal consists of two MLS loops, the headphone load needs to be connected during the second one)

- global equalization IR file (it is applied to all measurements)

- frequency response equalization IR file (it is only applied to the FR graph)

 

The graphs created include:

- frequency response (from impulse response, equalized; it does not average the response from multiple positions, though, which would be a useful feature)

- CSD (left and right channel)

- 500 Hz THD spectrum at 90 and 100 dB SPL (note: for the SPL values to be correct, the test file should be played at a volume setting at which 0 dBFS = 105 dB SPL - the drivers need to be able to handle this, and a long sine sweep at 100 dB)

- 55 Hz + 2000 Hz 4:1 IMD spectrum at 90 and 100 dB SPL

- 15000 + 16000 Hz 1:1 IMD spectrum at 90 and 100 dB SPL

- THD vs. frequency at 90 and 100 dB SPL

- THD vs. level at 50 Hz, from 80 to 105 dB SPL

- group delay

- impedance vs. frequency

 

The package also contains some sample graphs. However, since I did not use a high quality microphone and dummy head or artificial ear, these are not particularly accurate, and are really only examples.

post #934 of 937

Beyer DT 100 (400-ohm)

 

 

Measured without the artificial ear, but it looks close enough to the Golden Ears measurement and seems about what I hear.

 

Some actually do call these headphones neutral and accurate.

post #935 of 937

Anyone have an REW measurement response file for the HD25 they could send me?  I want to do a parametric eq on it.

post #936 of 937

Can you use these curves:

 

http://graphs.headphone.com/graphCompare.php?graphType=0&graphID[]=513&graphID[]=523&scale=20

 

 

http://jiiteepee.tripod.com/peqgui-10mc.html (read the documentation)

 

It's not perfect way but ...

post #937 of 937
Thread Starter 
Quote:
Originally Posted by Reticuli2 View Post
 

Anyone have an REW measurement response file for the HD25 they could send me?  I want to do a parametric eq on it.

 

Do you mean you want an impulse response file?

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